Grilled beef skewers with teriyaki sauce

From Serious Eats

We had these first at my nephew's birthday party and I've made them a few times myself.  Try and look for a thicker flank steak since you're going to slice against the grain before grilling.  This is also the best teriyaki sauce I've ever tasted.  Please note, this sauce takes several hours to put together.

For the teriyaki sauce-

1/2 cup mirin 

1/2 cup sake

1 cup soy sauce

1 cup pineapple juice

2/3 cup sugar (or less, I'm going to start to down on this going forward)

4 cloves of garlic, smashed

1 carrot, roughly chopped

6 scallion greens, chopped

Combine all the above ingredients, bring to a boil and then simmer until reduced to 1 1/2 cups, about an hour or until thickened

Strain through a fine mesh strainer

For the beef-

combine 1/2 cup of the teriyaki sauce and 

1/2 cup pineapple juice

Add to a bag and add the beef, toss to coat and let sit in the fridge for 1 hour but less than 4 hours. 

Heat grill to medium high heat.

Add beef to soaked skewers and grill 2 minutes a side.

Then brush each side with more sauce on each side, cooking 15 seconds each side.

Serve with more sauce, if desired.